Polyimide-assisted fabrication of highly oriented graphene-based all-carbon foams for enhancing thermal conductivity in polymer composites

Consequently, polymer/graphene thermal interface materials (TIM) typically exhibit high in-plane (IP) thermal conductivity (K), while the limited through-plane (TP) K is not as desirable in practical applications. Herein, vertically aligned high-quality polyimide/graphite nanosheets (PG) skeletons were developed to improve the TP K of polymer-based composites by a simple directional freezing strategy.

Notably, the graphene-based graphite nanosheets (GNs) are obtained from highly thermally conductive graphene film scraps by crushing. Water-soluble polyamic acid salt solution is used for direct dispersion of hydrophobic GNs fillers to achieve directional freezing. The polyimide has assisted the directional alignment of GNs and has been converted into graphite after graphitization.